JP2007062433A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device not requiring a connector and an external wire for transmitting a signal between a control device and a rotation position sensor, reducing cost and enhancing reliability of transmission of a position sensor signal. <P>SOLUTION: The control device 18 for the electric power steering device relating to the present invention is provided with a connection member 23 having a plurality of conductive plates 22; a magnetic sensor 24 provided on the connection member so as to be opposed to an end of a rotor shaft 2 and detecting a rotation position of the rotor 4; and a micro-computer for producing a drive signal for controlling drive of a semiconductor switching element from a position sensor signal, a torque sensor signal and a travel speed signal of the vehicle. Of the plurality of conductive plates 22, one end of the conductive plate 22c for the sensor is connected to the magnetic sensor 24 and the position sensor signal from the magnetic sensor 24 is inputted to the micro-computer through the conductive plate 22c for the sensor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric power steering apparatus including an electric motor that outputs an auxiliary torque to a steering wheel of a vehicle and a control device that controls driving of the electric motor.

2. Description of the Related Art Conventionally, there is known an electric power steering apparatus that includes an electric motor that outputs auxiliary torque to a steering wheel of a vehicle and a control device that drives and controls the electric motor, and the control device is attached to the electric motor. (For example, refer to Patent Document 1).
In this electric power steering apparatus, a resolver is attached to the output shaft of the electric motor as a rotational position sensor that detects the rotational position of the rotor.
When the control device is attached to the electric motor, the connector on the electric motor side and the connector on the control device side are fitted, and the resolver and the control device are electrically connected to notify the rotational position of the rotor. A position sensor signal from the resolver is input to the control device.

JP 2003-267233 A

In the electric power steering device, the resolver as the rotational position sensor is attached to the electric motor, and the position sensor signal of the rotor of the electric motor is input to the control device. In addition, a plurality of external wirings for connecting the connector on the electric motor side and the resolver are required.
As a result, there is a problem that the cost is increased and reliability in connection between the connector terminal on the electric motor side and the connector terminal on the control device side is lowered.

  An object of the present invention is to solve the above-described problems, and a connector and an external wiring for transmitting a signal between the control device and the rotational position sensor are not necessary, and the cost is reduced. In addition, an object of the present invention is to provide an electric power steering apparatus with improved reliability of transmission of position sensor signals.

  An electric power steering device according to the present invention includes an electric motor that outputs an auxiliary torque to a steering wheel of a vehicle, and a control device that controls driving of the electric motor, and the control device rotates the electric motor. A heat sink provided on the opposite side of the reduction gear connected to the rotor shaft of the rotor and a plurality of conductive plates provided between the heat sink and the rotor shaft to form a wiring pattern are insert-molded by an insulating resin. According to the connecting member integrated with each other, a rotational position sensor provided on the connecting member so as to face the end of the rotor shaft, and detecting the rotational position of the rotor, and torque assisting the handle A bridge circuit comprising a plurality of semiconductor switching elements for switching the current of the electric motor, a power board on which the bridge circuit is mounted, and A capacitor that absorbs a ripple of current flowing through the work board; and at least a position sensor signal from the rotational position sensor, a torque sensor signal from a torque sensor that detects a steering torque of the steering wheel, and a traveling speed signal of the vehicle. And a control board on which the microcomputer is mounted, and one end of the sensor conductive plate of the plurality of conductive plates is connected to the rotational position sensor. The position sensor signal from the rotational position sensor is connected to the microcomputer through the sensor conductive plate.

  The electric power steering apparatus according to the present invention eliminates the need for a connector and external wiring for transmitting a signal between the control device and the rotational position sensor, reduces the cost, and transmits the position sensor signal. Reliability is improved.

Embodiment 1 FIG.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the drawings, the same or equivalent members and parts are described with the same reference numerals.
1 is a circuit diagram showing an electric power steering apparatus according to Embodiment 1 of the present invention.
This electric power steering device drives an electric motor 1 that outputs an auxiliary torque to a vehicle handle (not shown), a control device 18 that controls driving of the electric motor 1, and the electric motor 1. A battery 50 for supplying the current of the steering wheel and a torque sensor 51 for detecting the steering torque of the steering wheel.
The electric power steering apparatus includes a power connector 35 in which the battery 50 and the control device 18 are electrically connected, and a vehicle-side signal connector 32 into which a vehicle-side signal such as a vehicle traveling speed signal is input from the vehicle side. And a torque sensor connector 33 in which the torque sensor 51 and the control device 18 are electrically connected.

  The electric motor 1 is a constituent element of a stator, and includes an armature winding 9 connected to three phases U, V, and W, and a sensor permanent magnet 6.

  The control device 18 includes a large-capacity capacitor 19 (about 2200 μF × 3) for absorbing the ripple component of the motor current IM flowing in the electric motor 1, a shunt resistor 29 for detecting the motor current IM, Equipped with semiconductor switching elements (for example, FETs) Q1 to Q6 that constitute a three-phase bridge circuit that switches the motor current IM according to the magnitude and direction of torque, and a shunt resistor 29 and semiconductor switching elements Q1 to Q6. This is a rotational position sensor that detects the direction of the magnetic field of the power board 20, the coil 26 that prevents electromagnetic noise generated during the switching operation of the semiconductor switching elements Q1 to Q6 from flowing out, and the permanent magnet 6 for sensor. And a magnetic sensor 24.

Further, the control device 18 is connected to one end of the shunt resistor 29 and calculates a supplemental torque based on a current detection means 52 for detecting a current flowing in the electric motor 1 and a steering torque signal from the torque sensor 51. The microcomputer 30 calculates the current corresponding to the auxiliary torque by feeding back the motor current IM and the rotational position of the rotor of the electric motor 1 detected by the magnetic sensor 24, and the semiconductor switching element according to a command from the microcomputer 30. A drive circuit 53 that outputs a drive signal for controlling the operation of Q1 to Q6, and a control board 21 on which the current detection means 52, the microcomputer 30, and the drive circuit 53 are mounted are provided.
The microcomputer 30 further includes a well-known self-diagnosis function in addition to an AD converter, a PWM timer circuit, etc., and always performs self-diagnosis as to whether the system is operating normally. The motor current IM is cut off.

In the electric power steering apparatus configured as described above, the microcomputer 30 receives the steering torque from the torque sensor 51 and the rotational position information of the rotor of the electric motor 1 from the magnetic sensor 24, and the vehicle-side signal connector 32. Is input with a traveling speed signal as one of the vehicle side signals.
Further, the motor current IM is fed back to the microcomputer 30 through the current detecting means 52 by the shunt resistor 29. In the microcomputer 30, a current control amount corresponding to the rotation direction command of the power steering and the auxiliary torque is generated from these information and signals, and each drive signal is input to the drive circuit 53.
In the drive circuit 53, when the rotation direction command and the current control amount are input, a PWM drive signal is generated and applied to the semiconductor switching elements Q1 to Q6.
As a result, the electric current from the battery 50 flows to the electric motor 1 through the power connector 35, the coil 26, and the semiconductor switching elements Q1 to Q6, and a required amount of auxiliary torque is output in the required direction.

At this time, the motor current IM detected through the shunt resistor 29 and the current detection means 52 is fed back to the microcomputer 30 so that it matches the motor current command Im sent from the microcomputer 30 to the drive circuit 53. Be controlled.
The motor current IM includes a ripple component due to the switching operation during PWM driving of the semiconductor switching elements Q1 to Q6, but is smoothed and controlled by the large-capacitance capacitor 19.
Further, the coil 26 prevents noise generated by the switching operation of the semiconductor switching elements Q1 to Q6 during PWM driving from being emitted to the outside and becoming radio noise.

Next, the structure of the above-described electric power steering apparatus will be described with reference to FIGS.
2 is a cross-sectional view of the electric power steering apparatus shown in FIG. 1, FIG. 3 is an exploded perspective view showing the electric power steering apparatus of FIG. 2, and FIG. 4 shows the control apparatus 18 shown in FIG. It is a figure when it sees from.
An electric motor 1 of this electric power steering apparatus includes a rotor shaft 2, an 8-rotor 4 in which a cylindrical permanent magnet 3 magnetized to 8 poles is fixed to the rotor shaft 2, and the rotor. 4 is fixed to the end surface of the small-diameter shaft end 10 on the side opposite to the output side of the rotor shaft 2 and has two poles corresponding to the magnetic pole position of the permanent magnet 3 of the rotor 4. And a magnetized sensor permanent magnet 6.
The stator 5 includes twelve salient poles 7 opposed to the outer periphery of the permanent magnet 3, an insulator 8 attached to the salient pole 7, and wound around the insulator 8, and U, V, and W 3 And an armature winding 9 connected to the phase. The three end portions of the armature winding 9 are respectively connected to three winding terminals 11 extending in the axial direction of the shaft end portion 10.

The electric motor 1 is fixed to the speed reducer 12. The speed reducer 12 includes a gear case 14 to which the housing 13 of the electric motor 1 is attached, a worm gear 15 provided in the gear case 14 for reducing the rotation of the rotor shaft 2, and teeth on the worm gear 15. And a combined worm wheel 16.
A spline is formed at the end of the worm gear 15 on the rotor shaft 2 side. A coupling 17 having a spline formed inside is press-fitted into an output side end of the rotor shaft 2. The coupling 17 and the end portion of the worm gear 15 are spline-coupled so that torque is transmitted from the electric motor 1 to the worm gear 15.

  The control device 18 for controlling the driving of the electric motor 1 includes a large-capacitance capacitor 19 (about 2200 μF × 3) for absorbing the ripple component of the motor current flowing in the electric motor 1 and an aluminum product having high thermal conductivity. It includes a heat sink 25, a power board 20 bonded to the surface of the heat sink 25 with an adhesive, and a control board 21 similarly bonded to the surface of the heat sink 25 with an adhesive.

  The control device 18 is mounted on the connection member 23 having a U-shaped cross section covering the thick portion 25a of the heat sink 25 and the bottom surface of the connection member 23 on the side opposite to the heat sink 25, and the magnetic field of the sensor permanent magnet 6 is mounted. A magnetic sensor 24 that is a rotational position sensor for detecting the direction of the circuit, a circuit case 27 that sandwiches the heat sink 25 in cooperation with the housing 13, and a coil 26 that is fixed to the circuit case 27 by welding to remove electromagnetic noise. And a cover 28 covering the opening of the circuit case 27.

  The power substrate 20 is made of, for example, a DBC (registered trademark of Toshiba Materials), and a copper plate is formed as a wiring pattern on an alumina ceramic substrate. High current components such as semiconductor switching elements (for example, FETs) Q1 to Q6 and a shunt resistor 29 are soldered and mounted on the wiring pattern on the power substrate 20.

The control board 21 is composed of a multilayer LTCC (low temperature fired ceramic) board. On the control board 21, peripheral circuit elements (small current components) including a microcomputer 30, a drive circuit 53, and current detection means 52 are conductively bonded. Implemented with agent.
Note that the drive circuit 53 and the current detection means 52 shown in FIG. 1 are omitted in FIG.

The connection member 23 has a U-shaped cross section, and the conductive plates 22 such as the motor conductive plate 22a, the sensor conductive plate 22c, and the power supply conductive plates 22e1 and 22e2 constituting the wiring pattern are insert-molded with an insulating resin. Has been configured.
At one side portion 23a of the connection member 23, one end portions of the plurality of motor conductive plates 22a are exposed from the insulating resin, and the one end portion constitutes a pad 22b for connecting to the power substrate 20 by wire bonding. is doing. A motor terminal Mm is formed at the other end of each motor conductive plate 22a. The motor terminal Mm is connected to the winding terminal 11 of the electric motor 1.

At the other side 23b of the connection member 23, one end of the sensor conductive plate 22c is exposed from the insulating resin, and this one end constitutes a pad 22d for connecting to the control board 21 by wire bonding. . The other end of the sensor conductive plate 22c extends to the vicinity of the center of the bottom of the U-shaped connecting member 23. A magnetic sensor 24 composed of a magnetoresistive element is provided on the surface of the bottom portion opposite to the heat sink 25, and the other end portion of the sensor conductive plate 22c is connected to the magnetic sensor 24 by welding.
Further, at the other side 23b of the connecting member 23, both ends of the power supply conductive plates 22e1, 22e2 are exposed from the insulating resin, and one end of each of the ends constitutes pads 22f1, 22f2 as power supply terminals. is doing.

  A pair of long holes 31 are formed in the heat sink 25 on both sides of the power board 20. In the connection member 23 on which the magnetic sensor 24 and the capacitor 19 are mounted, one side portion 23 a and the other side portion 23 b are inserted from the rotor 4 side through the long hole 31 and fixed to the heat sink 25.

  The magnetic sensor 24 faces the sensor permanent magnet 6, and the direction of the magnetic field of the sensor permanent magnet 6 rotates with respect to the magnetic sensor 24 as the rotor 4 rotates. As the motor rotates, the magnetic resistance changes, and as a result, the position of the rotor 4 is detected.

  The capacitor 19 is disposed on the opposite side of the control board 21 with the heat sink 25 interposed therebetween, and is disposed between the heat sink 25 and the housing 13 of the electric motor 1.

The control board 21 is disposed between the vehicle-side signal connector 32 and the torque sensor connector 33 and the other side portion 23 b of the connection member 23. A pad 34 formed at one end of each of the terminal of the vehicle signal connector 32 and the terminal of the torque sensor connector 33 and the pad 54 of the control board 21 are connected by wire bonding.
Similarly, the pad 22d of the connecting member 23 and the pad 55 of the control board 21 are also connected by wire bonding.
The vehicle-side signal connector 32 is a connector to which a traveling speed signal, an ignition signal, a CAN signal and the like, which are vehicle-side signals, are input via an external wiring, and the torque sensor connector 33 is a torque sensor via an external wiring. 51 is a connector to which a signal from 51 is input.

The power connector 35 provided adjacent to the vehicle-side signal connector 32 is a connector that is electrically connected to the vehicle battery 50, and the plus-side terminal of the power connector 35 is connected via the coil 26. 23 is electrically connected to a pad 22f2, which is a power supply terminal 23. The negative terminal of the power connector 35 is also electrically connected to the pad 22f1 that is the power supply terminal of the connecting member 23.
The power connector 35, the vehicle-side signal connector 32, and the torque sensor connector 33 are integral parts, and are integrally formed with a circuit case 27 made of an insulating resin.
The power connector 35, the vehicle side signal connector 32, and the cork sensor signal connector 33 may be separate components from the circuit case 27, respectively.

Next, an assembly procedure for the electric power steering apparatus configured as described above will be described.
First, the electric motor 1 is assembled.
First, the permanent magnet 3 was bonded and fixed to the outer peripheral surface of the intermediate portion enlarging in the radial direction of the rotor shaft 2, and the pole end 10 on the opposite side of the rotor shaft 2 was magnetized to two poles. The sensor permanent magnet 6 is bonded and fixed. Thereafter, the permanent magnet 3 is magnetized to 8 poles by a magnetizer based on the magnetization position of the sensor permanent magnet 6 to manufacture the rotor 4.
Next, the armature windings 9 of U, V, and W are wound around the 12 salient poles 7 of the stator 5 through the insulator 8 while moving the position by 120 degrees in electrical angle. A total of 12 windings are formed with 4 each phase. The U-phase armature winding is formed by connecting the winding start and winding end of each U-phase winding. Similarly, V-phase and W-phase armature windings are formed, and the winding ends of the U-, V-, and W-phase armature windings are connected to each other to form a neutral point. The beginnings of the U, V and W phase armature windings are connected to the winding terminals 11 respectively.
Thereafter, the stator 5 is press-fitted into the housing 13, and the outer ring of the bearing 36 is fixed to the housing 13.

  Next, after fixing the outer ring of the bearing 38 to the holder 37, the rotor shaft 2 of the rotor 4 is press-fitted into the inner ring of the bearing 38. Thereafter, the holder 37 in which the rotor 4 and the sensor permanent magnet 6 are incorporated is inserted and fixed in the housing 13 in which the stator 5 and the bearing 36 are incorporated.

Next, the assembly procedure of the control device 18 will be described.
First, components such as the microcomputer 30 and its peripheral circuit elements are joined on the control board 21 with a conductive adhesive, and the bare chip parts are electrically connected to the pattern on the control board 21 by wire bonding.
Further, components such as the semiconductor switching elements Q1 to Q6 and the shunt resistor 29 are joined on the power substrate 20 by soldering, and the semiconductor switching elements Q1 to Q6 that are bare chips are bonded to the pattern on the power substrate 20 by wire bonding. Connect electrically.

  Thereafter, the magnetic sensor 24 and the sensor conductive plate 22c of the connection member 23 are joined by welding, and the capacitor 19 and the power supply conductive plates 22e1 and 22e2 of the connection member 23 are joined by welding. The coil 26 is electrically connected between the conductive plate 27a2 of the circuit case 27 and the plus terminal of the power connector 35 by welding.

Next, the control board 21, the power board 20, the connection member 23, and the circuit case 27 on which components are individually mounted as described above are assembled to the heat sink 25. The control board 21 and the power board 20 are bonded and fixed to the heat sink 25 with an adhesive having good thermal conductivity. The circuit case 27 is bonded and fixed to the heat sink 25 with an adhesive to prevent water from entering between the circuit case 27 and the heat sink 25.
Next, the one side part 23 a and the other side part 23 b of the connection member 23 are inserted into the long holes 31 of the heat sink 25 from the side opposite to the fixing side of the power board 20, and the connection member 23 is fixed to the heat sink 25.

Next, the conductive plate 27a2 of the circuit case 27 and the power supply conductive plate 22e2 of the connecting member 23, and the conductive plate 27a1 formed with the negative terminal of the power connector 35 at one end and the power supply conductive plate 22e1 are electrically connected by welding. Connecting. Next, the pads 22b, 22f1, 22f2 of the connection member 23 and the power board 20 are electrically connected by wire bonding.
Similarly, the pad 22d of the connecting member 23 and the control board 21 are electrically connected by wire bonding, and the pad 34 of the vehicle-side signal connector 32, the pad 34 of the torque sensor connector 33, and the pad 54 of the control board 21 are connected. Are electrically connected to each other by wire bonding.

Next, the electric motor 1 and the control device 18 assembled separately are assembled.
First, the rubber ring 40 is attached to the groove 39 of the housing 13 of the electric motor 1, and the control device 18 is fixed to the housing 13 of the electric motor 1 with screws 41 as shown in FIG. 3. At this time, the sensor permanent magnet 6 and the magnetic sensor 24 are arranged to face each other.
Next, the winding terminal 11 of the electric motor 1 and the motor terminal Mm of the control device 18 are fixed with screws 43 and are electrically connected.
Finally, the cover 28 is bonded and fixed to the circuit case 27 of the control device 18 with an adhesive, and the assembly of the electric power steering device is completed.

  As described above, according to the electric power steering apparatus of the first embodiment, one end of the sensor conductive plate 22c is connected to the magnetic sensor 24 that is a rotational position sensor, and the position sensor signal from the magnetic sensor 24 is detected. Is input to the microcomputer 30 through the sensor conductive plate 22c, so that a connector and an external wiring for transmitting a signal between the control device and the rotational position sensor, which have been conventionally required, are not required, and the cost is reduced. And the reliability of transmission of the position sensor signal is improved.

  The magnetic sensor 24, which is a rotational position sensor, is provided on the connecting member 23 so as to face the sensor permanent magnet 6 provided at the end of the shaft end 10 of the rotor shaft 2, and the magnetic sensor 24 The rotational position of the rotor 4 can be detected by the change.

  The connecting member 23 is formed in a U-shaped cross section having one side portion 23a and the other side portion 23b opposite to the one side portion 23a, and is provided on the one side portion 23a. The motor terminal Mm, which is one end of 22a, is connected to the winding terminal 11 of the electric motor 1, and the pad 22b, which is the other end of the motor conductive plate 22a, is connected to the power board 20 and is connected to the other side 23b. Since the pads 22f1 and 22f2 of the provided power supply conductive plates 22e1 and 22e2 are connected to the battery 50 that supplies current to the power substrate 20, a path through which a large current flows is shortened, and power loss due to wiring is reduced. Performance is improved.

Further, since the power board 20 and the control board 21 are provided on the open surface on the opposite side to the rotor 4, the heat sink 25 can increase the area where the power board 20 and the control board 21 are arranged, The heat dissipation of the power board 20 and the control board 21 is improved.
Moreover, since the power board 20 and the control board 21 are provided on the same plane of the heat sink 25, electrical connection by wire bonding is facilitated, and workability is improved.

The heat sink 25 has a pair of long holes 31 formed on both sides of the power board 20, and one side portion 23 a and the other side portion 23 b of the connection member 23 are inserted from the rotor 4 side through the long holes 31 to the heat sink 25. Since it is fixed, the pads 22b, 22f1, 22f2 for wire bonding of the connecting member 23 and the power substrate 20 are arranged close to each other, the path through which a large current flows is shortened, and the power loss due to wiring is reduced, thereby reducing the performance. Will improve.
Further, as shown in FIG. 2, there is almost no difference in height between the surfaces of the wire bonding pads 22b, 22f1 and 22f2 of the connecting member 23 and the power substrate 20, and the workability of the wire bonding is facilitated and the workability is improved. improves.

  Further, the magnetic sensor 24 is composed of a magnetoresistive element, and the direction of the magnetic field with respect to the magnetic sensor 24 by the sensor permanent magnet 6 rotating with the rotation of the rotor 4 changes, and the resistance value increases with the change. Since the position of the rotor 4 is detected from the change in the direction of the magnetic field, the magnetic sensor 24 with respect to the sensor permanent magnet 6 is compared with the Hall element type magnetic sensor. The mounting position accuracy can be relaxed, and workability can be improved.

  Further, since the magnetic sensor 24 is connected to the sensor conductive plate 22c by welding, the mechanical strength at the connecting portion of the magnetic sensor 24 is high, and the proof strength of the connecting portion with respect to temperature change is high, so that the reliability of the apparatus is improved. Will improve.

  Further, the torque sensor connector 33 and the vehicle-side signal connector 32 are provided in the vicinity of one end portion of the control board 21, and the pad 22d of the sensor conductive plate 22c is provided in the vicinity of the other end portion. The bonding wires connecting the control board 21 and the control board 21 may be short, and the manufacturing cost is reduced.

Further, since the capacitor 19 is provided adjacent to the other side portion 23b of the connecting member 23, the distance between the capacitor 19 and the power board 20 is shortened, and the ripple component of the motor current flowing in the power board 20 is effectively absorbed. And radiation noise of the device can be suppressed.

  Further, since the capacitor 19 is disposed between the aluminum heat sink 25 and the housing 13 of the electric motor 1, the heat generated from the capacitor 19 is radiated to the heat sink 25 and the housing 13, and the capacitor 19 While the temperature rise can be suppressed, the durability of the capacitor 19 is improved.

In the above-described embodiment, the case where the magnetic sensor 24 composed of a magnetoresistive element is used has been described. However, the present invention is not limited to this, and high mounting accuracy is required as compared with the magnetoresistive element. In addition, although it is inferior in temperature characteristics, a Hall element or Hall IC may be used as the magnetic sensor.
In addition to the magnetic sensor, a photo sensor may be used as the rotational position sensor.

In the above-described embodiment, the electric power steering apparatus in which the number of poles of the permanent magnet 3 is 8 and the number of salient poles of the stator 5 is 12 has been described. However, the present invention is not limited to this combination. The number of poles and the number of salient poles may be combined.
The electric power steering apparatus is mounted in the engine room, and in order to ensure waterproofness, the circuit case 27 is bonded and fixed to the heat sink 25 with an adhesive, and is fitted in the groove 39 of the housing 13 of the electric motor 1. Although the rubber ring 40 is mounted and the electric motor 1 and the control device 18 are integrated, the adhesive and the rubber ring 40 may be deleted when the electric power steering device is mounted in the vehicle interior. .
Further, although the alumina DBC substrate is used as the power substrate 20, it is not limited to alumina, and may be a silicon nitride or aluminum nitride DBC substrate, and a copper plate pattern is bonded to these ceramic materials. It may be a metallized substrate. Further, it may be a metal substrate of aluminum or a copper base plate.
Moreover, although the multilayer LTCC board | substrate is used as the control board 21, a resin substrate may be sufficient.
The electric motor 1 is not limited to a brushless motor, and may be an induction motor or a switched reluctance motor (SR motor).

1 is a circuit diagram illustrating an electric power steering device according to Embodiment 1 of the present invention. FIG. It is sectional drawing which shows the electric power steering apparatus of FIG. FIG. 3 is an exploded perspective view showing the electric power steering apparatus of FIG. 2. It is a figure when the control apparatus of FIG. 2 is seen from the electric motor side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor, 2 Rotor shaft, 3 Permanent magnet, 4 Rotor, 6 Sensor permanent magnet, 12 Reduction gear, 15 Worm gear (reduction gear), 18 Control device, 19 Capacitor, 20 Power board, 21 Control board, 22 Conductive plate, 22a Motor conductive plate, 22c Sensor conductive plate, 22e1, 22e2 Power supply conductive plate, 23 Connection member, 23a One side, 23b Other side, 24 Magnetic sensor (rotational position sensor), 25 Heat sink, Q1 -Q6 Semiconductor switching element, 30 microcomputer, Mm motor terminal, 31 long hole, 32 vehicle-side signal connector, 33 torque sensor connector, 50 battery, 51 torque sensor.

Claims (10)

An electric motor that outputs an auxiliary torque to the handle of the vehicle, and a control device that controls driving of the electric motor,
The controller is
A heat sink provided on the opposite side of the reduction gear connected to the rotor shaft of the rotor of the electric motor;
A connection member in which a plurality of conductive plates that are provided between the heat sink and the rotor shaft and constitute a wiring pattern are integrated by insert molding with an insulating resin;
A rotational position sensor that is provided on the connecting member so as to face the end of the rotor shaft and detects the rotational position of the rotor;
A bridge circuit comprising a plurality of semiconductor switching elements for switching the current of the electric motor in accordance with torque assisting the handle;
A power board equipped with this bridge circuit,
A capacitor that absorbs the ripple of the current flowing through the power substrate;
A micro that generates a drive signal for controlling the driving of the semiconductor switching element from at least a position sensor signal from the rotational position sensor, a torque sensor signal from a torque sensor that detects a steering torque of the steering wheel, and a traveling speed signal of a vehicle. A computer,
And a control board on which this microcomputer is mounted,
One end of the conductive plate for sensors among the plurality of conductive plates is connected to the rotational position sensor, and a position sensor signal from the rotational position sensor is input to the microcomputer through the conductive plate for sensors. Electric power steering device.   The electric power steering apparatus according to claim 1, wherein the rotational position sensor is a magnetic sensor facing a sensor permanent magnet provided at an end of the rotor shaft. The connecting member is formed in a U-shaped cross section having one side and the other side facing the one side, and the motor conductive member provided on the one side of the conductive plate. One end of the plate is connected to the winding terminal of the electric motor, and the other end is connected to the power board,
3. The electric motor according to claim 1, wherein a power supply conductive plate provided on the other side portion of the conductive plates is connected to a battery that supplies a current to the power substrate. Power steering device.   4. The electric type according to claim 1, wherein the power board and the control board are provided on a surface of the heat sink opposite to the rotor. 5. Power steering device.   In the heat sink, a pair of long holes are formed on both sides of the power board, and the one side part and the other side part of the connection member are inserted through the long holes from the rotor side, and the connection member The electric power steering apparatus according to claim 4, wherein the electric power steering apparatus is fixed to the heat sink.   6. The electric power steering apparatus according to claim 2, wherein the magnetic sensor is configured by a magnetoresistive element.   The electric power steering apparatus according to any one of claims 2 to 6, wherein the magnetic sensor is connected to an end portion of the sensor conductive plate by welding.   The control board is provided with a torque sensor connector to which a torque sensor signal is input via an external wiring, a traveling speed connector to which a traveling speed signal is input, in the vicinity of one end, and in the vicinity of the other end. The electric power steering apparatus according to any one of claims 1 to 7, wherein the other end portion of the sensor conductive plate is provided.   The electric power steering apparatus according to any one of claims 3 to 8, wherein the capacitor is provided adjacent to the other side portion of the connection member.   10. The electric power steering apparatus according to claim 1, wherein the capacitor is disposed between the heat sink and a housing of the electric motor. 11.

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